1.of or being the lowest female voice2.of or being the highest male voice; having a range above that of tenor3.(of a musical instrument) second highest member of a groupalto clarinet or recorder

'alto' - used as a noun4.a singer whose voice lies in the alto clef5.the lowest female singing voice6.the highest adult male singing voice7.(of a musical instrument) the second highest instrument in a family of musical instruments8.the pitch range of the lowest female voice